Antonio Rosal

Production of pulp and energy using orange tree prunings.

The aim of this work was to chemically characterize orange tree prunings and use it in pulping and combustion processes. Soda-anthraquinone pulping of the main fraction of orange pruning (stems with a diameter > 0.5 cm) was simulated with polynomial and neurofuzzy models, that predicted pulp properties as a function of operating variables (155-185°C, 40-90 min, soda concentration, 10-16%) with errors less than 20%. The heating values (16,870 kJ/kg), the flame temperature (1150-2150 °C) and dew point temperature of fuel gas (47-53 °C) for the residual fraction from orange pruning (stems diameter < 0.5 cm and leaves) was determined and compared with other non-wood lignocellulosic materials. As a consequence the price of kJ obtained by combustion of this residual fraction is less than other lignocellulosic materials, much lower than those of fossil fuels.

Exploitation of hemicellulose, cellulose and lignin from Hesperaloe funifera

This work seeks the integral use of all major components of Hesperaloe funifera, separating hemicelluose by hydrothermal treatments; cellulose by pulping processes; and exploitation of lignin of pulping liquor by pyrolysis and gasification processes. By using sulfuric acid in the hydrothermal treatment (150-190 °C, 0-20 min after reaching operating temperature, 6-10 liquid/solid ratio, 0.1-0.5% sulfuric acid), the glucose and xylose of liquid fraction increase from 1.5% to 5.9%, and 4.0% to 12.4%, respectively; the yields of solid fraction decrease from 91.6% to 79.5%, and the lignin content increase from 23% to 32%. Pulps and paper sheets obtained from solid fractions hydrothermal treatments and from raw material pulped with diethanolamine, are worse than those obtained with soda-anthraquinone (Yield 57.8%; kappa number 24.9; Viscosity 711 mL/g; Brightness 54.8%; Tensile index 73.6 Nm/g; Stretch 2.84%; Burst index 6.13 kN/g and Tear index 1.69 mNm2/g). By acidification (pH 6) of soda pulping liquor it separate lignin-rich solids, which by pyrolysis gave a gas containing 1.13% H2, 31.79% CO and 1.86% CH4 by weight. Gasification of the same sample provided a gas containing 0.18% H2, 24.50% CO and 17.75% CH4.

Nitrogen recovery from wastewater using gas-permeable membranes: Impact of inorganic carbon content and natural organic matter

Gas-permeable membranes coupled with low-rate aeration is useful to recover ammonia (NH4+) from livestock effluents. In this study, the role of inorganic carbon (bicarbonate, HCO3-) to enhance the N recovery process was evaluated using synthetic effluents with various NH4+ to HCO3- molar ratios of 0.5, 1.0, 1.5 and 2.0. The study also evaluated the effect of increased organic matter on the NH4+ recovery using humic acids (3000-6000 mg L-1), and the N recovery from high-strength swine manure. The release of hydroxide from the HCO3- with aeration increased the wastewater pH and promoted gaseous ammonia formation and membrane uptake. At the same time, the recovery of gaseous ammonia (NH3) through the membrane acidified the wastewater. Therefore, an abundant inorganic carbon supply in balance with the NH4+ is needed for a successful operation of the technology. NH4+ removal efficiencies >96% were obtained with NH4+ to HCO3- ratios ≤1. However, higher molar ratios inhibited the N recovery process resulting in lower efficiencies (<65%). Fortunately, most swine manures contain ample supply of endogenous inorganic carbon and the process can be used to more economically recover the ammonia using the natural inorganic carbon instead of expensive alkali chemicals. In 4 days, the recovered NH4+ from swine manure contained 48,000 mg L-1. Finally, it was found the process was not inhibited by the increasing levels of organic matter in the wastewater evaluated.

Is vertebrate mortality correlated to potential permeability by underpasses along low-traffic roads?

Road permeability to animal movements depends among several factors on structures which, integrated in the road design, operate as safe conducts to mitigate vehicle collision and barrier effects. There is abundant evidence that wildlife makes use of such structures as safe passages to cross roads. We analyzed the spatial relationship between road drainage elements (N = 253; mostly culverts) as potential faunal underpasses, and mortality due to vehicle collisions in two seasons and on four relatively low-traffic roads (<5000 cars/day) traversing oak rangelands of western Andalusia (S Spain). Focusing on amphibians, reptiles and mammals, we recorded and located casualties (N = 238 individuals, 35 species) along these roads, identifying and characterizing all potential underpasses. Overall frequencies of casualties and spatial distribution were highly variable both within and among these roads. We obtained an estimation of potential permeability for the different roads. We detected, located and described a wide supply and a very variable pattern of drainage culverts and other underpasses, with differences among roads in passage attributes potentially affecting permeability for wildlife, such as spatial arrangement, number, density (frequency or concentration of passages) and dimensions. We used Mantel tests to assess spatial congruence of passages and road-killed animals. We applied generalized linear mixed models fitted by maximum likelihood through Akaike Information Criterion to explain the variation in the distance of the 238 casualties to the nearest underpasses, with road transect and season as random factors, and traffic intensity, speed and vertebrate class as fixed effects. Both road-killed animals and underpass distribution followed aggregated patterns, and casualties were not significantly related to underpasses along any of the 4 roads. There were no differences in distance of casualties to the nearest underpass for the three vertebrate classes. Although existing underpasses were abundant, we could not correlate potential permeability with reduced mortality along these roads, and other factors potentially affecting roadkill aggregations should be evaluated along with permeability assessment. Mitigation of road-caused mortality can still be greatly improved for these roads, through measures of reconditioning and proper management of existing underpasses, aiming to maximize road permeability and reducing major impacts upon animal populations of Andalusian rangelands.

Recovery of Ammonia in Raw and Co-digested Swine Manure Using Gas-Permeable Membrane Technology

Anaerobic digestion of agro-industrial and livestock waste generates considerable digestate volumes that are important sources of nitrogen (N). However, on some occasions, the high concentrations of N present in the digestates may represent an obstacle to its use locally as fertilizer, since it can cause an environmental impact (EC, 2000). This study analyzes the efficiency of gas-permeable membranes (GPM) in the recovery of the ammoniacal nitrogen (NH4+) present in the swine manure (SM, Control) and three digestates generated from the anaerobic co-digestion of mixtures of SM, fruit and vegetable sludge (FVS) from the vegetable industry (peppers and artichokes), and by-products of the tomato processing industry (TW) (skins and seeds), which were mixed at three different proportions [TW + FVS]: [SM]. Their NHx+ content was 2,240 mg L-1 for the SM and 4,670 to 5,370 for the digestate mixtures. Throughout the duration of the Necovery experiment (96 hours), the percentages of NH4+ removal and recovery achieved were consistent among treatments, approximatelly 78% and 96%, respectively. The recovery of NH4+ for the digestate mixtures seems to be dependent on the treatment time, since the potential of N recovery was higher when the treatment time increased. However, for the control experiment (SM), with lower N concentration, the maximum N recovery was obtained at the experimental time established, without increasing the treatment time.

Integral exploitation of olive tree pruning in the paper industry

This work seeks to obtain valuable products through an integral exploitation of lignocellulosic residues generated by agriculture, such as olive tree prunings. These sorts of residues are studied as alternative sources for lignocellulosic raw material in the paper industry and the black liquors generated could be used for several purposes, including the production of bioethanol. To reach these goals, a central composite factorial design was used to study the influence of operational variables [temperature (155, 170 and 185 ◦C), cooking time (40, 65 and 90min) and soda concentration (10, 14 and 18%)], on pulps and paper sheets properties obtained from olive tree prunings, likewise black liquors generated in these pulping processes were set up to enable both yeast strains (Saccharomyces cerevisiae CECT 1170 and Pichia stipitis CECT 1922) to be capable of doing an alcoholic fermentation at 30 and 26 ◦C respectively, 5.5 pH, and under 150 rpm shaking. The results were similar to those obtained with other agricultural residues which are alternative sources for the paper industry. The best values of the physicochemical properties of cellulose pulps, such as Kappa number (31.98) or viscosity (716.11mL/g) and the paper sheets, such as tensile index (608m) or tear index (1.655mNm2/g), were reached operating to high values of soda concentration and temperature and slight cooking times. However, the black liquors of this study were not an optimal medium for the bioethanol production. It might be due to the important presence of inhibitors in the fermentation processes, such as 5hydroxymethyl-furfural.